BoilerFaultCodesYour boiler is heating up too quickly because water isn't flowing through the system properly, causing it to shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water shortage, temperature rise too quick
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the water temperature is rising much faster than the system can handle. The most common reason is a lack of circulation, often caused by a failing pump or a blockage in the pipework that prevents the heat from being moved away from the boiler quickly enough. It can also be triggered if there is air trapped in the heat exchanger or if the system water pressure has dropped too low.
This issue is frequently seen during the first cold spell of autumn when heating systems are turned back on after a long summer break, which can cause internal pump components to seize.
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 bar on the display.Ensure all radiator valves and isolation valves under the boiler are fully open.Bleed your radiators to remove any trapped air pockets.If pressure is low, use the filling loop to top it up.
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